A cycle or other similar vehicle driven or used by a rider generally has a frame which has at least one surface engaging member. Typically the surface engaging member comprises one or more wheels. Attached to the cycle frame is a seat for supporting the rider on the cycle during operation. In most instances, a rigid seat post or seat support apparatus is used to connect or attach the seat to the frame. In those apparatus, any impact loading applied to the cycle frame is transmitted directly through the rigid seat support apparatus to the seat. If the rider is supported by the seat, the impact loading often results in discomfort for the rider.
As an alternative, some seat support apparatus have been employed that have special features designed to dampen the impact loading and absorb the shock transmitted between the cycle frame and the cycle seat. Impact dampening seat support apparatus attempt to reduce the impact transmitted from the cycle frame to the cycle seat and rider to improve comfort to the rider when the cycle is subjected to the impact loading during operation.
In some previous impact dampening seat support apparatus, the seat support apparatus have metal parts which move relative to each other during impact loading. After movement, the parts are biased back toward an at rest position by biasing structure included on the seat support apparatus. One problem encountered with some seat support apparatus of this type is that some of the parts slidably engage each other during impact loading and subsequent biasing. The metal parts that slidably engage require external lubrication to prevent excessive wearing and grinding of the parts against each other. This results in lubricated parts being exposed to contact by the rider and also requires periodic lubrication by the rider. Furthermore, if the sliding parts are made from certain metals, they may rust or corrode, further diminishing the sliding capability of the parts. Wearing and grinding of the sliding parts of the cycle seat support apparatus is especially serious when the sliding surfaces are at angles relative to any loading transmitted through the cycle seat support apparatus.
Another problem sometimes encountered with conventional impact dampening cycle seat support apparatus having sliding or moving parts is caused by the necessity for structure in the apparatus for preventing rotational movement of the seat relative to the frame. Elongated structures having round cross-sectional shapes which slidably engage each other will rotate relative to each other unless structure is provided to limit rotation. To address this problem, one cycle seat support apparatus described in U.S. Pat. No. 4,736,983 employs an additional key member attached to an inner surface of a sleeve where the key member projects inwardly toward a post to engage a notch in the post to prevent rotational movement of the post relative to the sleeve. Another type of apparatus which also has an outer sleeve and an inner post is described in U.S. Pat. No. 4,182,508 and employs a single tooth projecting outwardly from the post which slides within an elongated slot formed in the sleeve. These structures are sometimes difficult to manufacture; cause a loss of stability; and prevent the sliding parts from securably engaging one another during operation.
Another problem encountered with conventional impact dampening apparatus is that some employ numerous small parts to limit rotation and/or dampen the impact loading. U.S. Pat. No. 4,456,295 discloses an impact dampening apparatus with five coil springs positioned inside and outside a box-like housing and several bolts with nuts inserted through the housing. Other apparatus employ intricate and costly structure such as hydraulics to dampen the impact loading and bias the moving parts to the at rest position.
Various other problems encountered with some impact dampening cycle seat support apparatus include that the apparatus is often bulky and may take up excessive space between the cycle frame and the cycle seat. Furthermore, some cycle seat support apparatus may add excessive weight to the cycle.
It is clear that there has been a continuing need for improvements in cycle seat support apparatus to provide for impact dampening for loads transmitted between a cycle frame and a cycle seat while addressing the above recited problems, or similar problems.